1. Field of the Invention
The present invention relates to the provision of coverings or facings for walls and the exterior surfaces of buildings that simulate or give the appearance that the wall or surface is constructed of another type of material, such as brick or stone. More particularly, the present invention relates to a system and method of providing an artificial facing upon a building wall which provides an impression of being constructed of materials such as bricks laid one upon another or in a variation of a natural stone or rock wall even though the wall itself may be formed of a less substantial construction such as a wooden construction or the like.
2. Preliminary Discussion and Description of Related Art
Wall panels and coverings that are simulative of or resemble materials such as brick, masonry or stone, as well as numerous processes for making the same, are known. In particular, there has been a need for a wall facing and process for constructing a wall facing that simulates as realistically as possible a natural brick or stone wall construction, that is durable and not subject to cracking or fissures, and in addition that requires a lesser number of skilled laborers working in a coordinated manner but rather can be completed in sections rather than requiring substantial completion of an entire wall surface area at one time.
U.S. Pat. No. 2,162,861 issued to L. Polak on Jun. 30, 1939 and as illustrated in FIGS. 1 and 2 teaches a method of providing an artificial wall covering involving the application of a sheet of waterproof material (6) to a wall, followed by attachment of a metal lath or mesh netting (9) or other reinforcing to the wall on top of the waterproof material. Next, several layers or coatings of an unset cement or plaster material are applied over the wire lath. The first layer or coating (10) is a “scratch coat” the preferred composition of which is disclosed as being a thick coating of lime plaster that is forced through the wire lath or mesh, completely enclosing it and filling the spaces between the lath and waterproof sheet. A composition of one part cement, two parts of lime, and three parts of sand is suggested. The sand need not be limited to fine grade, because the first layer is not part of the final coating exposed to the weather. The lime, however, provides extra adherence. After the first layer has substantially set, a second preferably thinner coating (11) of colored plaster called the “mortar joint coat” is applied to the face of the first coat. The color is appropriate to whatever the coating is to appear to be, for example, red if the wall is to appear as a brick wall, but any other color is appropriate. In general, the second layer is of finer materials than the first layer, and is damp proof to protect the first coat from moisture. Finally, when the second layer is set, a third layer (13) called the “finish color coat” in the form of a finer and even thinner plaster material preferably having a contrasting color from the second coat is applied to the face of the second coat. After the third layer of plaster has set slightly, and before the second coat has completely set, a straightedge or other suitable tooling such as a U-shaped blade is used to form grooves (13) in the finish by removing portions of the plaster entirely through the third coat of plaster plus partly into the second coat of plaster. The grooves are for the purpose of simulating brickwork, tiles or other surface materials (14) by creating the simulated appearance of mortar joints between the simulated bricks, tile or other desired simulative appearance. Additional colors can be added on top of the “finish color coat” to create a more realistic look or appearance.
This previous process of simulation has proved to be very successful and has been used with good results for many years, being applied largely under the trademark Brickote™. However, the Brickote™ process does have certain disadvantages. For instance, because of the necessity to apply all the layers while the cement and plaster are somewhat set, but only partially set, and because it is difficult to match adjacent areas, it is also necessary to assemble large amounts of materials sufficient to finish a job as a unit. The process, therefore, requires a large fast-working, well coordinated crew of workers, a requirement which is not always easy to fulfill under modern conditions, particularly as the Brickote™ simulated siding process is often applied by local contractors who may find it difficult to assemble an experienced crew on fairly short notice.
The present inventor realizing the drawbacks of the former method of applying the Brickote™ process has unexpectedly discovered that an alternative process can be used which is adaptable to discontinuous application and can be applied to large surfaces, one section at a time in basically a start and stop mode of application. A particular difficulty with stopping a conventional Brickote™ coating application operation is that if a partially completed surface dries out, too much cracking is liable to occur and any attempt to repair such cracks leaves a clearly evident defect which is almost impossible to disguise and which is also liable to increase in severity over time.
The present invention solves the previous difficulties in a clear and innovative way by providing in a preferred embodiment two cement layers upon a single wire reinforcement, such as galvanized wire lath, but instead of adding color to the individual plaster or cement layers on top of the scratch coat as in the just-described arrangement so that when the cement or plaster is cut down to form the outline of the bricks or blocks, the contrasting color of the underlying layers becomes evident, no coloring is added to the layers. In the present inventor's process, after the first coating has partially set up, a second or outer layer of plaster is applied to the face of the first coating. Then, when the second layer has partially set up, divisions or grooves are cut to form the simulated blocks, bricks, tile or the like. Such divisions or grooves are cut down near to the bottom of the two layers so that individual masses of plaster are defined, which individual masses set up and start drying separately from each other, and because of their lesser mass, have little tendency to crack and spall such as would or will occur if the prior Brickote™ process was used and interrupted.
In the present invention after the individual “bricks”, “tiles”, or “blocks” have set up, which under normal conditions typically takes a day or two, after which an outer coat comprised of an acrylic finish can then be applied to protect the whole surface. The colors of the blocks, tile, or bricks are thus provided by means of the outer coat or coating of acrylic pigment or paint carefully matched to the colors described, although a colored cement coat followed by a clear acrylic coat could also be provided. Meanwhile, the divisions or grooves between the simulated blocks, tiles, or bricks are left without an outer acrylic coating and serve as restrictive drying zones from which moisture can evaporate evenly to the atmosphere. The size of each of the simulated bricks, blocks or tiles is small enough in surface area so that these accumulations or masses of materials do not dry out significantly at differential speeds and spalling and cracking is thereby inhibited. The key to the process therefore is to divide a surface into a number of individual restricted area surfaces which are not large enough to develop significant transverse differential drying from the side which is liable to crack the surface and cause spalling and cracking of the coating. While the acceptable size of such individual units varies with actual conditions, it has been found that units which replicate conventional brick, stone, block, and tile wall covering are all within the acceptable range under the range of normal conditions. The vapor resistant acrylic coating once applied prevents large scale drying from the surface once it is itself dried, and the size of the uncoated surfaces between the simulated bricks, blocks or tiles are not large enough to allow the coated areas to significantly dry differentially and transversely to cause significant differential drying tensions. The acrylic coating layer is compatible with the underlying cement material because it is water-based and tends to dry along with the underlying cementitious material. Additional masonry acrylic coatings may be applied over the first coating to change the color, or to add texture and the like to the finished surface. Once this has dried, a conventional mortar is applied in the divisions or grooves serving as simulative mortar joints, and thus forming a finished simulated wall covering. The mortar may be colored or shaded as needed to match the coloring of the finished wall surface.
Because the simulated block, bricks or tiles are maintained in a size which is significantly restricted to prevent sufficient differential drying across a surface and to encourage drying of such material at a rate such as not to encourage cracking or spalling, the individual blocks do not spall or crack. The application of a moisture-proof coating on the surface furthermore prevents contained moisture from escaping vertically through the surface, thereby forcing moisture to escape through the uncoated simulated mortar in the joints between the units such that the drying rate is held within limits necessary to prevent spalling and cracking. This means that the drying rate is held to a minimum at any point dependent upon the space between the bricks, blocks or tiles. In other words, if the size of a unit surface feature is held to a size small enough to allow significant drying to occur only between blocks, bricks or tiles, cracking is found not to occur. This allows small sections of a whole wall surface to be applied even on alternate days or other time units because the entire surface is applied in individual surface units.